I’m 100% sure the memory speed is not the issue here. I cannibalised memory from two older laptops, and I have a mix of 2667 MT/s and 2133 MT/s in my 11th gen Framework, which means the entire system can only run at 2133 MT/s, yet it performs perfectly fine. It idles below 40°C, boosts up to 37W for long enough and then sustains 28W after that in Cinebench R23 multi, where it scores 5389 points. And this is only an i5-1135G7.
Lower memory speed is never supposed to do anything weird to thermals or power management. In most workloads it barely makes any difference at all. In GPU-heavy workloads such as games it might make a larger difference, but we weren’t talking about any of those.
I’m pretty sure OP’s laptop has an actual thermal issue if it idles at >50°C and can’t sustain anywhere near 28W and still hits 95°C in 2 seconds. It’s very likely that re-applying thermal past or just reseating the cooler or cleaning the fan would fix it. Definitely something that Support can deal with.